Love the process, even when it hurts.

The rule of four

Suggestive of PE: - Westermark sign: peripheral hyperlucency of the pulmonary arterial tree resulting from blood flow being cut off by the PE. - Hampton hump: peripheral, wedge-shaped lung opacity representing pulmonary infarction. An ipsilateral pleural effusion is also commonly present with this sign (pulmonary infarction is the typical cause of PE-associated pleural effusion). - Fleischner sign: Enlargement of the pulmonary artery resulting from increased pressure proximal to the PE.